1. A "manual" change. This is when you use your once-per-turn battle position
change on a monster, during your Main Phase 1 or 2, to change it from attack
position to defense position or vice versa. This includes a Flip Summon. There
are some restrictions on when you can do this (see below).

2. A change because of a card effect. Examples: Enemy Controller, Zero
Gravity, Guardian Sphinx, Book of Moon and Tsukuyomi.

A manual change can only be performed during your Main Phase 1 or 2. There are
3 exceptions that will prevent you from manually changing a monsters battle
position:
Exception #1: You cannot manually change the battle position of a monster if it
declared an attack that turn (even if the attack was negated or a replay occurred).

You CAN change the battle position of a monster manually if it was Summoned or
Set, but not by the turn player. Example: Cyber Jar Summons a monster on the
opponents side of the field, and the turn player uses Change of Heart to take
control of it, then Flip Summons it that same turn. This is a legal play (as long
as none of the 3 exceptions exist).